Engineering Commons^™

Evaluating Descriptive Metrics Of The Human Cone Mosaic, Robert F. Cooper, Melissa A. Wilk, Sergey Tarima, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To evaluate how metrics used to describe the cone mosaic change in response to simulated photoreceptor undersampling (i.e., cell loss or misidentification).

Methods: Using an adaptive optics ophthalmoscope, we acquired images of the cone mosaic from the center of fixation to 10° along the temporal, superior, inferior, and nasal meridians in 20 healthy subjects. Regions of interest (n = 1780) were extracted at regular intervals along each meridian. Cone mosaic geometry was assessed using a variety of metrics − density, density recovery profile distance (DRPD), nearest neighbor distance (NND), intercell distance (ICD), farthest neighbor distance (FND), percentage of …

Image-Based Quantification Of 3d Morphology For Bifurcations In The Left Coronary Artery: Application To Stent Design, Laura M. Ellwein, David S. Marks, Raymond Q. Migrino, Dennis Foley, Sara Sherman, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

Background

Improved strategies for stent‐based treatment of coronary artery disease at bifurcations require a greater understanding of artery morphology.

Objective

We developed a workflow to quantify morphology in the left main coronary (LMCA), left anterior descending (LAD), and left circumflex (LCX) artery bifurcations.

Methods

Computational models of each bifurcation were created for 55 patients using computed tomography images in 3D segmentation software. Metrics including cross‐sectional area, length, eccentricity, taper, curvature, planarity, branching law parameters, and bifurcation angles were assessed using open‐sources software and custom applications. Geometric characterization was performed by comparison of means, correlation, and linear discriminant analysis (LDA).

Results …

Mg2+ Differentially Regulates Two Modes Of Mitochondrial Ca2+ Uptake In Isolated Cardiac Mitochondria: Implications For Mitochondrial Ca2+ Sequestration, Christoph A. Blomeyer, Jason Bazil, David F. Stowe, Ranjan K. Dash, Amadou Ks Camara

Biomedical Engineering Faculty Research and Publications

The manner in which mitochondria take up and store Ca²⁺ remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca²⁺ uptake and a complex Ca²⁺ sequestration mechanism in mitochondria. But how Mg²⁺ regulates these different modes of Ca²⁺ uptake as well as mitochondrial Ca²⁺ sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca²⁺ by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl₂ in the …

Automatic Detection Of Cone Photoreceptors In Split Detector Adaptive Optics Scanning Light Ophthalmoscope Images, David Cunefare, Robert F. Cooper, Brian P. Higgins, David F. Katz, Alfredo Dubra, Joseph Carroll, Sina Farsiu

Biomedical Engineering Faculty Research and Publications

Quantitative analysis of the cone photoreceptor mosaic in the living retina is potentially useful for early diagnosis and prognosis of many ocular diseases. Non-confocal split detector based adaptive optics scanning light ophthalmoscope (AOSLO) imaging reveals the cone photoreceptor inner segment mosaics often not visualized on confocal AOSLO imaging. Despite recent advances in automated cone segmentation algorithms for confocal AOSLO imagery, quantitative analysis of split detector AOSLO images is currently a time-consuming manual process. In this paper, we present the fully automatic adaptive filtering and local detection (AFLD) method for detecting cones in split detector AOSLO images. We validated our algorithm …

Emerging Investigators Series: Virus Mitigation By Coagulation: Recent Discoveries And Future Directions, Joe Heffron, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Waterborne viruses are widespread and persistent in the environment. Coagulation is an effective process for mitigating viruses in drinking water. This review examines recent studies of virus mitigation by coagulation processes in the context of the latest scientific advances. Virus sorption is impacted by electrostatic forces, as well as the hydrophobic effect, steric hindrance, hydrodynamics and interactions with the water matrix. Organic matter in the water may hinder or enhance sorption, depending on virus structure and environmental factors. In addition to physical separation in flocs, coagulation processes have been shown to inactivate viruses. This review evaluates reports of virus inactivation …

Conceptual Design Of Sleeve Rotor Synchronous Reluctance Motor For Traction Applications, Patel B. Reddy, Kevin Grace, Ayman M. El-Refaie

Electrical and Computer Engineering Faculty Research and Publications

Synchronous reluctance machines are very appealing for high speed traction motor design due to their robustness, simple structure, absence of magnets, and simple control. The absence of magnets means that synchronous reluctance (SynRel) machines are not susceptible to price variability and sustainability of rare-earth materials. Moreover, there are no concerns about demagnetisation or uncontrolled generation mode. However, the challenge of achieving a good constant power to speed ratio is dependent on the mechanical aspects of the design. Conventional SynRel designs perform poorly compared with the permanent magnet machines due to the presence of bridges and/or centre posts in absence of …

Longitudinal Imaging Of Microvascular Remodelling In Proliferative Diabetic Retinopathy Using Adaptive Optics Scanning Light Ophthalmoscopy, Toco Yuen Ping Chui, Alexander Pinhas, Alexander Gan, Moataz Razeen, Nishit Shah, Eric Cheang, Chun L. Liu, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

Purpose

To characterise longitudinal changes in the retinal microvasculature of type 2 diabetes mellitus (T2DM) as exemplified in a patient with proliferative diabetic retinopathy (PDR) using an adaptive optics scanning light ophthalmoscope (AOSLO).

Methods

A 35-year-old T2DM patient with PDR treated with scatter pan-retinal photocoagulation at the inferior retina 1 day prior to initial AOSLO imaging along with a 24-year-old healthy control were imaged in this study. AOSLO vascular structural and perfusion maps were acquired at four visits over a 20-week period. Capillary diameter and microaneurysm area changes were measured on the AOSLO structural maps. Imaging repeatability was established using …

Relating Anaerobic Digestion Microbial Community And Process Function, Kaushik Venkiteshwaran, Benjamin T.W. Bocher, James Maki, Daniel Zitomer

Biological Sciences Faculty Research and Publications

Anaerobic digestion (AD) involves a consortium of microorganisms that convert substrates into biogas containing methane for renewable energy. The technology has suffered from the perception of being periodically unstable due to limited understanding of the relationship between microbial community structure and function. The emphasis of this review is to describe microbial communities in digesters and quantitative and qualitative relationships between community structure and digester function. Progress has been made in the past few decades to identify key microorganisms influencing AD. Yet, more work is required to realize robust, quantitative relationships between microbial community structure and functions such as methane production …

An Algorithm For Constrained One-Step Inversion Of Spectral Ct Data, Rina Foygel Barber, Emil Y. Sidky, Taly Gilat Schmidt, Xiaochuan Pan

Biomedical Engineering Faculty Research and Publications

We develop a primal-dual algorithm that allows for one-step inversion of spectral CT transmission photon counts data to a basis map decomposition. The algorithm allows for image constraints to be enforced on the basis maps during the inversion. The derivation of the algorithm makes use of a local upper bounding quadratic approximation to generate descent steps for non-convex spectral CT data discrepancy terms, combined with a new convex-concave optimization algorithm. Convergence of the algorithm is demonstrated on simulated spectral CT data. Simulations with noise and anthropomorphic phantoms show examples of how to employ the constrained one-step algorithm for spectral CT …

Development Of A Wireless Mobile Computing Platform For Fall Risk Prediction, Akm Jahangir Alam Majumder

Dissertations (1934 -)

Falls are a major health risk with which the elderly and disabled must contend. Scientific research on smartphone-based gait detection systems using the Internet of Things (IoT) has recently become an important component in monitoring injuries due to these falls. Analysis of human gait for detecting falls is the subject of many research projects. Progress in these systems, the capabilities of smartphones, and the IoT are enabling the advancement of sophisticated mobile computing applications that detect falls after they have occurred. This detection has been the focus of most fall-related research; however, ensuring preventive measures that predict a fall is …

The Role Of Household Antimicrobials In The Proliferation Of Antibiotic Resistance During Anaerobic Digestion, Daniel Elliott Carey

Dissertations (1934 -)

Antimicrobial chemicals in consumer personal care products have been found to increase antibiotic resistance in pure culture studies. Although many studies focus on antibiotic resistance development pertinent to medical scenarios, resistance developed in natural and engineered environments might be significant and has become an emerging concern for human health. This dissertation focuses on the antimicrobial chemicals triclosan and triclocarban. These compounds are distinctly different from antibiotics and are used in products like soaps that are labelled as “antibacterial”. Municipal wastewater treatment plants receive triclocarban and triclosan loads higher than most contaminants of emerging concern because they are frequently used in …

Investigation Of The Use Of A Plasticizer-Polymer Sensor Coating With Improved Long-Term Stability In The Liquid Phase, Laura Jeanne Alderson

Master's Theses (2009 -)

Benzene is one of the volatile organic compounds present in crude oil and gasoline. Leakage from underground storage tanks or hazardous waste sites can introduce benzene contamination into nearby groundwater. Benzene is a known carcinogen and its exposure is limited by the Environmental Protection Agency to 5 parts per billion (ppb) in drinking water. Early, accurate detection of the presence of benzene contamination in groundwater supplies is extremely important. Shear horizontal surface acoustic wave (SH-SAW) devices with a chemically sensitive coating can be used for the detection of volatile organic compounds in liquid, such as BTEX (benzene, toluene, ethylbenzene and …

Ramifications Of Projectile Velocity On The Ballistic Dart Penetration Of Sand, Peter Anthony Sable

Master's Theses (2009 -)

With the advent of novel in-situ experimental measurement techniques, highly resolved quantitative observations of dynamic events within granular media can now be made. In particular, high speed imagery and digital analysis now allow for the ballistic behaviors of sand to be examined not only across a range of event velocities but across multiple length scales. In an attempt to further understand the dynamic behavior of granular media, these new experimental developments were implemented utilizing high speed photography coupled with piezo-electric stress gauges to observe visually accessible ballistic events of a dart penetrating Ottawa sand. Projectile velocities ranged from 100 to …

Application Of A Multi-Zone Model For The Prediction Of Species Concentrations In Rapid Compression Machine Experiments, David Wilson

Master's Theses (2009 -)

Accurate chemical kinetic models, which predict species evolution and heat release rates in chemically reactive systems, are essential for further advancements in fuel and combustion technology. An experimental facility that is widely used for evaluating the accuracy of kinetic models is a rapid compression machine (RCM), which creates a well-defined reaction environment by compressing a reactive mixture inside a chamber. Generally, RCM experiments are conducted in order to obtain ignition delay data. However, chemical speciation data provides greater insight into reaction pathways, and is therefore a more rigorous benchmark for validating kinetic models. In order for a chemical kinetic model …

Modeling And Investigation Of Refrigeration System Performance With Two-Phase Fluid Injection In A Scroll Compressor, Rui Gu

Master's Theses (2009 -)

Vapor compression cycles are widely used in heating, refrigerating and air-conditioning. A slight performance improvement in the components of a vapor compression cycle, such as the compressor, can play a significant role in saving energy use. However, the complexity and cost of these improvements can block their application in the market. Modifying the conventional cycle configuration can offer a less complex and less costly alternative approach. Economizing is a common modification for improving the performance of the refrigeration cycle, resulting in decreasing the work required to compress the gas per unit mass. Traditionally, economizing requires multi-stage compressors, the cost of …

A Principal Component Analysis Investigation Of Drop Landings For Defining Anterior Cruciate Ligament Injury Risk Factors, Emily Schaefer

Master's Theses (2009 -)

Injury to the anterior cruciate ligament (ACL) has been widely investigated through observational video analysis and laboratory based cadaveric, motion capture and computer simulation models. With the greater incidence of injury in the female population, recent emphasis has been placed on understanding ACL injury mechanisms in females. By using our understanding of injury mechanisms and prospective studies, injury prediction methods can be created. Once injury can be reliably predicted, training methods can be implemented to reduce likelihood of injury and avoid devastating consequences. There is a need for a reliable way to reduce motion capture data obtained in a laboratory …

Least-Squares Mapping From Kinematic Data To Acoustic Synthesis Parameters For Rehabilitative Acoustic Learning, Xiangyu Zhou

Master's Theses (2009 -)

Thousands of people suffer from dysarthria resulting from neurological injury of the motor component of the motor-speech system, and need to rely on alternative methods to communicate in daily life, such as body language or text-to-speech [1] . However, there are currently very few effective rehabilitative therapies for helping these patients improve their speech. Because of this, research is needed to develop better rehabilitative therapies. One such area of research is the use of involuntary acoustic learning. The Speech and Swallowing lab at Marquette University has an Electromagnetic Articulography (EMA) system to collect kinematic data and a software system called …

Cyclic Behavior Of A Hybrid Light Gauge And Hss Mezzanine Structural System, Michael John Kren

Master's Theses (2009 -)

Cold-formed steel is emerging as an alternative material in the building industry to hot-rolled steel for smaller buildings and indoor structures also called mezzanines. Cyclic testing of a full-scale mezzanine structures composed of cold-formed structural channel beams connected to hollow structural steel (HSS) columns cap plates using wedge expansion anchors at the base plate to generate rotation restraint, is performed in this research. The characteristics of the structure will be explained by displaying full experimental results of structural testing. Unfortunately, limited experimental data outlining the behavior of these structures is available and design criteria is very limited. Thus, there is …

Structural-Functional Brain Connectivity Underlying Integrative Sensorimotor Function After Stroke, Benjamin Thomas Kalinosky

Dissertations (1934 -)

In this dissertation research project, we demonstrated the relationship between the structural and functional connections across the brain in stroke survivors. We used this information to predict arm function in stroke survivors, suggesting that the tools developed through this research will be useful for prescribing individualized rehabilitation strategies in people after stroke. Current clinical methods for rehabilitating sensorimotor function after stroke are not based on the locus of injury in the brain. Instead, therapies are generalized, treating symptoms such as weakness and spasticity. This results in outcomes that are highly variable, with severity of impairment immediately following stroke as the …

Thermal Microfluidic Devices; Design, Fabrication And Applications, Benyamin Davaji

Dissertations (1934 -)

This thesis investigates the thermal actuation and temperature measurement methods in microfluidic devices. We designed and fabricated microfluidic devices with various functionalities such as: bio sensing, particle counting, microscale calorimetry, and cellular temperature measurement. All of these functionalities use thermal measurement methods. When quantitative measurements are required, the label-free nature of thermal measurement methods, along with its simple readout, make it a powerful candidate for lab on a chip and bio sensing/detection applications. In this work, thermal measurement methods are used to characterize bio-samples, measure concentrations, study thermal responses, and even perform particle cytometry. However, thermal measurement methods are known …

Novel Convergence Results In Nonlinear Filtering, Jennifer Lynn Bonniwell

Dissertations (1934 -)

In this dissertation, the discrete-time extended Kalman filter is analyzed for its ability to attenuate finite-energy disturbances, known as the H-infinity property. Though the extended Kalman filter is designed to be a locally optimal minimum variance estimator, this dissertation proves that it has additional properties, such as H-infinity. This analysis is performed with the extended Kalman filter in direct form. Since this form reduces assumptions placed on the system in previous works on convergence and H-2 properties of the extended Kalman filter, the extended Kalman filter used as a nonlinear observer for noise-free models is revisited using the direct form …

Injury Risk Assessment Of The Femur In Children With Osteogenesis Imperfecta, Jessica Marie Fritz

Dissertations (1934 -)

Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and decreased bone mass, which leads to high rates of bone fracture. OI has a prevalence of 1/5,000 to 1/10,000 in the United States. About 90% of persons with OI have a genetic mutation in the coding for collagen type I, which is the major protein of connective tissues, including bone. While its prevalence classifies it as a rare disease, it is the most common disorder of bone etiology. Until recently, little was known about the mechanics and materials of OI bone or their impact on fracture risk. …

Optimal Schedules In Multitask Motor Learning, Jeong Yoon Lee, Youngmin Oh, Sung Shin Kim, Robert A. Scheidt, Nicolas Schweighofer

Biomedical Engineering Faculty Research and Publications

Although scheduling multiple tasks in motor learning to maximize long-term retention of performance is of great practical importance in sports training and motor rehabilitation after brain injury, it is unclear how to do so. We propose here a novel theoretical approach that uses optimal control theory and computational models of motor adaptation to determine schedules that maximize long-term retention predictively. Using Pontryagin’s maximum principle, we derived a control law that determines the trial-by-trial task choice that maximizes overall delayed retention for all tasks, as predicted by the state-space model. Simulations of a single session of adaptation with two tasks show …

Integrating Nanosphere Lithography In Device Fabrication, Tod V. Laurvick, Ronald A. Coutu Jr., Robert A. Lake

Electrical and Computer Engineering Faculty Research and Publications

This paper discusses the integration of nanosphere lithography (NSL) with other fabrication techniques, allowing for nano-scaled features to be realized within larger microelectromechanical system (MEMS) based devices. Nanosphere self-patterning methods have been researched for over three decades, but typically not for use as a lithography process. Only recently has progress been made towards integrating many of the best practices from these publications and determining a process that yields large areas of coverage, with repeatability and enabled a process for precise placement of nanospheres relative to other features. Discussed are two of the more common self-patterning methods used in NSL (i.e. …

Alterations In Cortical Sensorimotor Connectivity Following Complete Cervical Spinal Cord Injury: A Prospective Resting-State Fmri Study, Akinwunmi Oni-Orisan, Mayank Kaushal, Wenjun Li, Jack Leschke, B. Douglas Ward, Aditya Vedantam, Benjamin Kalinosky, Matthew D. Budde, Brian D. Schmit, Shi-Jiang Li, Viashnavi Muqeet, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Functional magnetic resonance imaging (fMRI) studies have demonstrated alterations during task-induced brain activation in spinal cord injury (SCI) patients. The interruption to structural integrity of the spinal cord and the resultant disrupted flow of bidirectional communication between the brain and the spinal cord might contribute to the observed dynamic reorganization (neural plasticity). However, the effect of SCI on brain resting-state connectivity patterns remains unclear. We undertook a prospective resting-state fMRI (rs-fMRI) study to explore changes to cortical activation patterns following SCI. With institutional review board approval, rs-fMRI data was obtained in eleven patients with complete cervical SCI (>2 years …

Instrumented Lumbar Corpectomy And Spinal Reconstruction Comparing Rhbmp-2/Compression-Resistant Matrix, Rhbmp-2/Absorbable Collagen Sponge/Ceramic Granules Mixture, And Autograft In Two Different Devices: A Study In Sheep, Jeffrey M. Toth, David G. Schwartz, Jean-Piere Mobasser, Joseph Williams

Biomedical Engineering Faculty Research and Publications

Study Design. Fusion success with rhBMP-2 and autograft in titanium or PEEK corpectomy devices was evaluated in a sheep lumbar corpectomy model. The 6 treatment groups included titanium mesh or PEEK corpectomy devices filled with rhBMP-2 on a compression-resistant matrix (CRM) carrier; rhBMP-2 in a morselized absorbable collagen sponge (ACS) carrier combined with resorbable ceramic granules; and autograft.

Objective. The aim of this study was to determine fusion rates associated with 2 different preparations of rhBMP-2 as well as autograft in an instrumented ovine lumbar corpectomy model 6 months postoperatively.

Summary of Background Data. Vertebral reconstruction with corpectomy devices requires …

Development Of High-Order PN Models For Radiative Heat Transfer In Special Geometries And Boundary Conditions, Wenjun Ge, Michael F. Modest, Somesh Roy

Mechanical Engineering Faculty Research and Publications

The high-order spherical harmonics () method for 2-D Cartesian domains is extracted from the 3-D formulation. The number of equations and intensity coefficients reduces to (N+1)2/4 in the 2-D Cartesian formulation compared with N(N+1)/2 for the general 3-D formulation. The Marshak boundary conditions are extended to solve problems with nonblack and mixed diffuse-specular surfaces. Additional boundary conditions for specified radiative wall flux, for symmetry/specular reflection boundaries have also been developed. The mathematical details of the formulations and their implementation in the OpenFOAM finite volume based CFD software platform are presented. The accuracy and computational cost of the 2-D Cartesian are …

Bond–Slip Behavior Of Fiber-Reinforced Polymer/Concrete Interface In Single Shear Pull-Out And Beam Tests, Tayyebeh Mohammadi, Baolin Wan, Kent A. Harries

Civil and Environmental Engineering Faculty Research and Publications

It has been assumed that the fiber-reinforced polymer/concrete interface is subjected to in-plane shear condition when intermediate crack debonding failure occurs. Therefore, the single shear pull-out test results are often used to predict the intermediate crack debonding failure in beams. In this study, the behavior of fiber-reinforced polymer-strengthened concrete beams and single shear pull-out specimens were studied experimentally and numerically. The bond–slip behavior of the fiber-reinforced polymer/concrete interface was obtained by single shear pull-out and beam tests. In all beam specimens, a concrete wedge located at the edge of the notch detached with the fiber-reinforced polymer debonding failure. This phenomenon …

Faculty Intellectual Property In Capstone Design Projects, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Reports on the Capstone Design challenge, focusing on design challenges for the participants. By focusing on the design process and allowing students to gain hands-on experience in design, they help prepare students for careers in engineering. In many capstone design courses, students design a product or device to solve a problem and build and test a prototype to verify and validate the design. Student teams are often advised by some combination of industry sponsors, clinical advisors, and/or faculty advisors. Faculty advisors serve as technical advisors to the teams and provide guidance to keep them on track. They are not members …

Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie

Electrical and Computer Engineering Faculty Research and Publications

In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom …